When loading and unloading cargo units of uniform size, in the first hand standard shipping containers, in connection with ships, an overhead crane is often used. This crane is provided with a gantry runway, which extends over a ranging area at the quay being continued by a cantilever portion reaching out from the edge of the quay. Alternatively a crane having a long, swinging arm may be used. These cranes are movable on rails along the quay. The containers are usually stored in several superimposed layers, and in order to be able to place containers properly as deck cargo the crane operator's cage must be located at a considerable height above the level of the quay.
This implies definite difficulties for the operator to select containers in the proper sequence and to attach the lifting means in a safe manner.
A standard shipping container is at its upper corners provided with strong boxes, having openings for gripping means, and the lifting means of the crane includes a yoke provided with operable gripping means for engagement with said openings.
The work of the operator should be considerably reduced, and the cargo handling should be much faster, as compared to the conventional procedure, if the operator had to care for the lifting only, while the selection of the container and the guiding of the yoke towards the same was performed by other personell.